hopcraft



- 1N0 Model.) 3 Sheets-Sheet 1'.

L. HOPORA FT.

FURNACE FIRE GRATE. No. 450,018. Patented Apr. 7, 1891.

(No 110461.).- a sheets sheet 2..

L. HOPGRAFTQ FURNACE FIRE GRATE.

No. 450,018. Patented Apr. 7,1891. v

(No Model.) 3 Sheets-Sheet 3.

L. HOPORAFT. FURNACE FIRE GRATE.

No. 450,018. Patented Apr. 7,1891.

I F.|G.6.

AAA/MA UNITED STATES ATENT OFFICE.

LElVIS HOPORAFT, OF LONDON, ENGLAND, ASSIGNOR. TO THE HOPORAFT FURNACE COMPANY, LIMITED, OF SAME PLACE.

FURNACE FlRE-GRATE.

SPECIFICATION forming part of Letters Patent No. 450,018, dated. April *7, 1891.

Application filed December 26, 1839. Serial No. 335,060. (No model.) Patented in England February 13, 1889, No. 2,581.

To all whom it may concern: said radial arms corresponds to that of the Be it known that I, LEWIS HOPORAFT,enothers, so that when in position on the radial gineer, asubject of the Queen of Great Britain, arms each fire-bar is level. V residing at No. 26 \Vest Bank, Stamford Hill, The radial arms G rest upon a ring E, fixed 5 London, in the countyof Middlesex, England, to the tube H. (See Fig. 1.) This ring is have invented new and useful Improvements made with a shoulder D, inclosing an annuin and Relating to Furnace Fire-Grates, (for lar space, as shown in Fig. 1, within which are which I have obtained British Letters Patany suitable number of conical rollers 0, runent No. 2,581, dated February13, 1889,) of ning in suitable bearings formed on a loose 10 which the following is a specification. ring A. The trunnion-ringB is fitted on the This invention comprises certain improvetop of the screw-conveyer tube J and does ments on the invention for which Letters not rotate. The upper end of the said screw- Patent were granted to me numbered 404,706 conveyor tube J is made of a globular shape, and dated June at, 1889. and the lower part of the trunnion-tube B, 6

r 5 The improvements consist, first,in the conwhich fits thereover is made of a similar struction of the radial arms for carrying the shape, the two forminga joint for the purpose circular bars; second, of means for tilting the of altering the inclination of the grate when grate independently of the worm-conveyer desired. The outside of the trunnion-tubeB tube; third, in the construction of the worm is provided with trunnions A working in 2o conveyer and the tube, so that the fuel may fixed bearings carried bysuitable brackets or be fed in any desired direction instead of standards formed on the screw-conveyer tube vertically or horizontally only, as heretofore; J, so as to support the tube B and prevent it fourth, in means for regulating the feed of turning on a vertical axis. A groove A is the fuel, and, fit'th, in providing an outer made in the outer circumference of the ring 25 case, so that the furnace complete may be fit- E, within which works a chain L for rotating ted into or withdrawn from an internally fired the grate; but other means may be adopted boiler when desired. it found convenient.

In order that my invention may be more The screw conveyer is constructed so as to fully understood and carried into practice, I convey the coal in any desired direction and 3o willnow proceed to describe the same with is provided with means for regulating the supreference to the accompanying drawings, in ply of coal to the furnace. I construct the which simila'r letters indicate corresponding screw conveyer in sections and string them parts throughout. loosely upon a non-rotatable rod or bar M,

Figure 1 is a longitudinal section of a fur- (shown in dotted lines in Fig. 1,) curved to 35 nace fire-grate constructed according to this the shape of the direction in which it is deinvention. Fig. 2 shows the whole arrangesired to convey the coal, so that the said rod ment provided with an outer casing ready for or bar M is always central in the conveyerfitting into an internally-fired boiler. Fig. 8 tube J. Onto the upper end of the saidrod is an enlarged plan of one of the gimbals M is aflixed ahead Aiwhich rests against the 40 used in the screw conveyer and Fig. 4. is an last section of the screw and keeps it in posienlarged plan of one of the sections of the tion. The other end of the rod M passes screw conveyer. Fig. 5 is an elevation of a through the center of the worm-actuating radial arm. Fig. 6 is a partly-sectional eleshaft S and is produced outward and provation of the screw conveyer, and shows the vided with a spiral or other spring B bear- 5 45 arrangement adopted for regulating the feed; ing against a washer O with adjusting lockand Fig. 7 is a section on the line mm, Fig. 0. nuts D (See Fig. 1.) The tension of the The radial arms G are vertically sinuous or spring therefore tends to pull the rod forsinuous only on their upper surfaces, as shown ward out of the tube J, causing the head A in Figs. 1 and 5, and the fire-bars when placed to bear against the last section, thus com- 50 thereon conform to the wavy shape of the rapressing all the sections and so keeping the dial arms, the sinuosities of each of which gimbals in their places. Between each two sections I place a loose gimbal or universal joint N, provided with two pairs of trunnions 0, each pair being at right angles to the other pair. (See Fig. One pair of trunnions takes into recesses or bearings P in one section and the other pair of trunnions into bearings in the next section. Each section of the worm conveyer is constructed in the form of a boss or collar Q, with a screw wing or blade R (see Fig. 4) constructed thereon in such a manner that when fitted together the wings or blades are continuous and form an Archimedeanscrew around the bosses or collars, as shown in Fig. 1.

To regulate the feed of the conveyer, I construct the boss or collar q of the first section, or the section immediately under the hopper, in the form of a truncated cone with a blade or wing r, which only extends the same distance from the center of the boss as the wings or blades on the other sections, as shown in Fig.1 and in detail in Figs. 6 and 7. Thus as the boss or collar (1 becomes thicker the wing or blade 9 becomes correspondingly less, and will therefore take up and feed along a smaller quantity of coal at its thicker than it would at its thinner end. The first or conical section is provided with a sleeve 8, riding loose on the shaft S, which said shaft Sis rigidly affixed to the boss Q of the second section. This shaft S is provided with a pin or thread T, extending partly round its circumference and of the same pitch as the pitch of the Archimedean screw. This said pin or thread T works in a corresponding groove formed on theinside of the boss q of the first section. The wing r is prolonged beyond the end of the boss q and is provided with a small shoulder or bend t, and then continued so as to lie parallel with and close against the under side of the wing R of the second section. By this arrangement as the first section is moved away from the second there will be no gap in the Archimedean screw. The first section is actuated as follows: The sleeve 3 terminates in a collar to with a suitable number of holes around its circumference, into which the end of a tommy or lever may be placed and provided with a set-screwv. Fig. 6 shows the conical section close up to the next section, so as to feed the smallest amount of coal possible. To alter the feed, I turn the collar u by means of a tommy or handlever. The groove on the boss q works over the thread T, formed on the shaft S, and the continuation of the wing 7 works along and under the wing R on the second section until the desired thickness of the cone is beneath the hopper, when I fix it by means of the set-screw r. The other extreme position of the collar u is shown by the dotted lines in Fig. 6. There is an annular recess in the base of the cone, into which takes the boss U on the cover of the conveyer tube J.

WVhen it is desired to fit the furnace firegrate in aninternally-fired boiler, I construct a casing V smaller in size than the furnacetube, so that it may easily slide therein without jamming against the plates, rivets, or other projections, and within this casing I build the furnace-bridge NV and fit together the various parts forming the furnace-grate, as shown in Fig. 2. The casing V is then, with the furnace-grate therein, placed in position in the furnace-tube and secured by means of suitable flanges constructed or formed on or affixed to the casing V, whereby the said casing may be bolted to the boilerplates.

IVhat I olain1'is- 1. In combination with a central rotating cylinder or tube H, the sinuous radial arms G for carrying the concentric fire-bars, and a suitable feeding device for conveying the fuel to the fire-bars, substantially as and for the purposes set forth.

2. A screw conveyer constructed in sections fitted together by gimbals or universal joints N, working on a central rod M, bent to the required shape, substantially in the manner described and illustrated.

3. The feed-regulating device consisting of a conical section with a prolonged wing or blade 1' and a thread T, working in a corresponding groove formed in the boss q and actuated by the sleeve s and collar u, substantially as and for the purpose hereinbefore set forth and illustrated.

4. A casing V, in which the various parts of the furnace-grate are fitted together, and a bridge V built therein for expeditiously fitting the furnace fire-grate into internallyfired boilers, substantially as and for the purpose hereinbefore set forth.

LEWIS HOPORAFT.

Witnesses:

F. W. GoLBY, 54E Fleet Street, London, England.

'1. F. BARNES, 17 Gracechtwch Street, London, England. 

